A car of mas m moving at a speed `upsilon` is stopped in a distance x by the friction between the tyres and the road. If the kinetic energy of the car is doubled, its stopping distance will be

Options

A. `8x`
B. `4x`
C. `2x`
D. `x`

Answer

C

Explanation

If a is the deceleration due to the force of friction f, then
`2ax = upsilon^2`
or `1/2 m upsilon^2 = "max or " KE = f x ( because f = ma)`
Thus if KE is doubled, x is also doubled. Hence the correct choice is (C)